Method of and apparatus for forming blackboard surfaces



Oct. 24, 1933. J. F. JOHNSON ET AL 1,932,215

METHOD OF AND APPARATUS FOR FORMING BLACKBOARD SURFACES Filed .April 27.1931 5 Sheets-Sheet l ggw v Oct- 24, 1933- J. F. JOHNSON El AL METHOD OFAND APPARATUS FOR FORMING BLACKBOARD SURFACES Filed April 27. 1931 5Sheets-Sheet 2 V517 :75 John E J/wzaam Oct- 24, 1933. J. F. JOHNSON ETAL 1,932,215

METHOD OF AND APPARATUS FOR FORMING BLACKBOARD SURFACES Filed April 27,1931 5 Sheets-Sheet 3 Jo/zn ff 159727780729 1, 029% aqkzmaiz,

iii 14L?- Oct. 24, 1933. J JOHNSON r AL 1,932,215

METHOD OF AND APPARATUS FOR FORMING BLACKBOARD SURFACES Filed April 27,1931 5 Shets-Sheet 4 b y: g5-

Oct. 24, 1933- J. F. JOHNSON ET AL 1,932,215

METHOD OF AND APPARATUS FOR FORMING BLACKBOARD SURFACES Filed April 27,1931 5 Sheets-Sheet 5 w w w Z w w R a W E g M h. H P 8 w z, F80 W, 4 OJU y w 1 a c w i ll 5 5 0J6 MW 9 W W 5 8 8 40 a w 4 E3: 6 6 U, o, a A "Jm; i b M "w 5 f M J l 5/ w 1 n 4 fl PH 3 F Patented Oct. 24, 1933 UNITEDSTATES METHOD OF AND APPARATUS FOR- FORM- ING BLACKBOARD SURFACES JohnF. Johnson and Robert B. Lawton, Chicago Heights, 11]., assignors toWeber Costello Co., Chicago Heights, 11]., a corporation of IllinoisApplication April 27, 1931. Serial No. 533,196

4 Claim.

This invention relates to the method of forming blackboard surfaces andimproved apparatus whereby the method may be practiced.

Heretofore, in the manufacture of blackboards, it has been the usualpractice to provide a slab of material, which constitutes the body ofthe blackboard, and to apply a plurality of coats of various substancesto the surface of this material to form the writing surface of theblackboard. These coatings of material have been applied in various waysamong which were by means of a brush or by spraying the material ontothe surface. Inasmuch as the various devices for applying the materialwere manually operated, the results obta ned were unsatisfactory in thatthe coatings were usually uneven and not uniform. The surface was oftenstreaked and was by no means pleasing to the eye.-

In order to overcome the above and other objections to the presentmanner of manufacturing blackboards, it is an object of this inventionto provide an improved method for depositing a uniform coating ofmaterial upon the surface of the body material of the blackboard.

It is a further object of this invention to provide novel means wherebythe surface of a continuously moving stock material may be uniformlycoated with a finishing material.

It is a further object of this invention to provide novel means wherebya spray nozzle may be moved over the surface of a continuously movingstock material in such a manner as to deposit thereon a uniform surfaceor coating of finishing material.

Another object of this invention is to provide a novel method of coatingblackboard surfaces wherein the fumes from the coating material will notpollute the surrounding atmosphere.

In accordance with the general features of our invention, we propose toprovide a conveyor for carrying the blackboard along at a uniform rateof speed beneath a spray nozzle which is mounted in such manner as to bemovable back and forth above the surface of the stock material at auniform rate of speed. With this arrangement, the coating material willbe deposited uniformly on the surface of the blackboard and the finishedsurface will be free from streaks and unevenness which were heretoforein evidence.

It is contemplated that a series of coatings of material wll be appliedto the surface of the slab of blackboard material. The underlying coatswill be of a color composition and the last coat will contain anabrasive material such as carborundum.

Another feature of our invention is in the provision of an enclosurewithin which the spraying operation is carried on, this enclosure beingprovided with louvers or openings for the circulation of a stream of airwhich will carry off the fumes and thus prevent pollution of thesurrounding atmosphere.

Other objects and features of this invention will more fully appear fromthe following detailed description taken in connection with theaccompanying drawings which illustrate a single embodiment thereof andin which F. gure 1 is an elevation of a machine embodying the featuresof our invention;

Figure 2 is an end elevation of the machine as viewed from the feed endof the conveyor;

Figure 3 is an enlarged side elevation in which the housing forming thespraying compartment is in section to show the ventilating opening inthe side thereof and-the details of the spraying mechanism;

Figure 4 is an enlarged plan view of the machine in which the housingforming the spraying compartments is in section to show the mechan'smfor oscillating the spray nozzle over the surface of the blackboard tobe sprayed;

Figure 5 is a vertical transverse section of the machine, takensubstantially on line V-V of Figure 3;

Figure 6 is an enlarged fragmentary view showing the details of themechanism for oscillating the spray nozzle;

Figure 7 is an enlarged fragmentary sectional view of the mechanism foroscillating the spray nozzle, taken substantially on line VII-VII ofFigure 6;

Figure 8 is an enlarged fragmentary section through the rack and pinionconnection to the spray nozzle head, taken substantially on lineVIII-VIII of Figure 5.

As disclosed in the drawings, the machine of our invention comprises ingeneral a supporting frame structure, a conveyor, a spraying mechanism,and power means for actuating the conveyor and spraying mechanisms.

More specifically, the supporting structure for the conveyor mechanismconsists of a frame A having spaced uprights 10 and 11, the uprights 10being secured at their ends to lower and upper rails 12 and 13respectively, and the uprights 11 to lower and upper rails 14 and 15respectively, suitable cross bars 16 being provided in order to make theframe sufficiently rigid. A shaft 17 is rotatably supported in bearings18-18 on the uprights 10 and 11 at one end of the frame A and hassecured thereto at spaced intervals a plurality of sprocket wheels 19. Asimilar shaft 20 is rotatably supported at its ends in bearings 21-21which are secured to the uprights 10 and 11 at the other end of frame A.Fixedly secured to and rotatable with the shaft 20 are a plurality ofsprocket wheels 22 which are spaced apart so as to be in alignment withthe sprocket wheels 19 at the other end of frame A. A chain 23 istrained around each set of sprocket wheels, that is, each set consistingof a sprocket wheel 22 and a sprocket wheel 19, this chain extendingover the upper surface of the frame A where it is confined within achannel shaped member 24 which extends longitudinally of and issupported upon the frame A. Each chain 23 passes over an idler pulley23a on a transversely extending shaft 24a. which is supported on frame Aso as to be adjustable to vary the tension of the chain. The chains 23are of such thickness that they project above the walls of the channels24 so that when a stock material, in this instance a slab of blackboardmaterial 25, ,is placed thereon, it will be transported longitudinallyof the frame A.

The conveyor mechanism is driven from a motor 26 which is supported onthe lower rails of the frame A. The shaft 27 of this motor is providedwith a driving pinion 28 which is connected by means of a chain 29 to asprocket wheel 30 connected through a clutch 31 to a shaft 32. The shaft32 is rotatably supported in bearings 3333 on the spaced uprights 34-34.This shafthas secured thereto at one end a worm 35 which meshes with aworm wheel 36 on the shaft 37 which extends transversely of the frame Aand is supported thereon for rotation by suitable bearings. The shaft 37carries a plurality of sprocket wheels 38 which are spaced at intervalstherealong and are connected through chains 39 to a corresponding numberof sprocket wheels 40 on the shaft 20, each chain 39 being trained overan idler 41 which is adjustable for varying the tension of the chain.

The clutch 31 which is of a type well known in the art is actuated by ashifting fork 42 on a rocker shaft 43 extending transversely of theframe A. This rocker shaft is connected to a lever 44 by means of whichthe clutch mechanism may be actuated.

A supporting frame B for the spraying mechanism extends above frame Aand at right angles thereto and is formed by the upright members 34 andsimilar upright members 45 which are outwardly spaced on either side offrame A and are interconnected by transverse bars 46 which providesufficient rigidity.

The spraying mechanism comprises a spray nozzle C which is carried atone end of a pivotally mounted arm 47. This nozzle is of a type wellknown in the art and preferably consists of a tubular member 48 which isvertically disposed and to which a supply of air is connected by meansof a hose 49. The air supply is controlled by a suitable valve which isactuated by a lever member 50. Connected to the member 48 adjacent thelower end thereof is an angularly disposed conduit 51 for injecting thematerial to be sprayed into the air stream passing through member 48. Avalve 52 is provided in the member 51 for controlling the supply ofspray material. The spray material is supplied through a hose 53 whichis connected to the member 51.

The arm 47 is supported in a head 54 at the upper end of a verticallydisposed shaft 55 which is rotatably supported in bearings 5656 ontransverse frame members 57-57 extending between and connected at theirends to the uprights 34 and 45. Disposed above and abutting the lowerbearing 56 is a collar 58 which is secured to the shaft 55 forconstraining the same against axial movement downwardly through thebearings.

The hose 49 and the hose 53 are connected to the head 54 which isprovided with suitable connections 59 and 60 on the upper surfacethereof,

these connections being adapted for receiving hose connections 61 and62, respectively, from the sources of supply for the air and thematerial to be sprayed. A handhold 63 is formed at the opposite end ofthe arm 47 from the nozzle C by means of which the arm may be shiftedaxially through the head 54 thereby permitting an adjustment of the arcof travel of the nozzle.

The spraying mechanism is driven from a worm 64 on the main drivingshaft 32. The worm 64 meshes with a worm wheel 65 on the lower end of avertically disposed shaft 66 which is rotatably supported in suitablebearings 67 and held against downward axial movement by collars 68secured thereto and bearing against the upper surfaces of the respectivebearings.

The upper end of the shaft 66 has secured thereto a horizontallydisposed cam member 69 having its peripheral surface in engagement witha roller 70 at one end of a bar '71 which is mounted for axial movementin a guide member 72 secured to the frame B. The other end of the member71 has a slot '73 for receiving an end of a rack '74, this rack beingpivoted to the end of the member 71 by means of a bolt or pivot pin 75.The rack 74 meshes with a pinion 76 which is secured to the shaft 55.

The roller 70 is held in engagement with the peripheral surfaces of thecam 69 by means of springs 77 which are disposed on either side of themember 71 and extend parallel thereto, these springs being connected atone end to a bar 78 fixedly secured to the guide member 72, and at theirother end to a bar 79 which is secured to the rack 74. A coil spring 80surrounds the member 71. One end of this spring bears against a collar81 which is secured to the member 71 by a pin .32 and the other end ofthe spring bears against a stationary member 83 which loosely surroundsthe member 71 and issupported on a bracket 84 in such a manner as to belaterally movable. The upper bearing 56 is grooved at its upper end asat 85 for receiving the rack 74 for reciprocable movement therein. Therack is retained in this groove by means of a plate 86, which extendsover the upper surface of the rack where it passes through the groove.

The cam 69 is of such shape that when it is rotated rectilinear motionwill be imparted to the rack, and the pinion 76 will be rotated so as tocause the arm 47 to oscillate back and forth and move the nozzle C at auniform speed relative to the slab of blackboard material 25 which isbeing fed under the nozzle by means of the conveyor mechanism. By virtueof this rack and pinion connection, and since the cam 69 is providedwith diametrically opposed dwell positions Where the movement of therack is reversed, a tension spring 8'7 is secured at one end to the arm47 and at the other end to the upright members 45 for compensating forthe lost motion in the driving mechanism. The spring 87 is assisted inthis respect by a resilient stop member 89 which is mounted on one ofthe transverse members 57 so as to be engaged by the arm 47 at one endof its arcuate movement.

In order to prevent dissemination into the sur-j rounding atmosphere ofthe spray discharge from the nozzle, a housing is provided whichsubstan-' tially encloses that portion of the machine where I.

which are welded, riveted or otherwise secured to the side members. Theback 91 terminates at its lower edge adjacent the conveyor mecha nismand is spaced above the same sufficiently to enable the slab ofblackboard material on the conveyor to pass thereunder. This housing isopen on the side toward the feed end of the conveyor to permit operationof the arm 47. A duct 93 is arranged at each side of the housing andcommunicates with the interior thereof through an opening 94 in the sidemember contiguous thereto. Each of these ducts is connected with asuction system so that the fumes arising from the spraying process willbe carried away and not pollute the surrounding atmosphere.

Since the nozzle C is carried past the lateral edges of the blackboardwhich is being sprayed, and since the nozzle does not immediately startupon its return movement by virtue of the dwell positions in the cam 69as previously described, lateral troughs 95 are arranged along each sideof the conveyor beneath the lateral edges of the blackboard material tobe sprayed. These troughs receive the material which is discharged fromthe spray nozzle during the time when it is at the dwell positions, thespray material deposited therein being thereby drained off into asuitable container and not wasted.

The operation of the machine of our invention is briefly as follows:

Having the clutch control lever 44 in the offposition, the motor 26 isstarted by means of suitable control equipment. It is preferable at thistime to have the nozzle C disposed over one of the troughs 95 in orderto facilitate adjustment thereof without wasting the spray material. Thespray is then turned on and properly adjusted by means of the valve 52and the valve actuating member 50. A supply of slabs of blackboardmaterial to be sprayed having previously been arranged on the conveyorsystem in end to end relationship, the machine is now ready to bestarted.

This is accomplished by moving the clutch control lever 44 to therunning .position. In this position the motor will drive the conveyorand carry the slabs of blackboard material under the spray at a uniformspeed. Simultaneously with the movement of these slabs, the arm 4'? willoscillate with a uniform speed and carry the nozzle C back and forthacross the slab. This uniform movement of the arm 4'7 is effected bymeans of the rotation of the cam 69. Rotation of this cam causes themember 71 to reciprocate back and forth, and since this member isconnected to the rack which engages the pinion 76, the rectilinearmotionof the member 71 will be converted into rotary motion through thepinion. At the end of the arcuate movement of the arm 47, the arm willremain stationary for a short interval due to the diametrically opposeddwell positions formed in the cam surface. the slab blackboard materialto be advanced a predetermined amount before the nozzle is again carriedacross the surface thereof. The continuous advancement of the blackboardslab and the movement of the nozzle back and forth thereover continuesas long as the'machine is running and these movements are so timed thatthe material sprayed on the surface of the blackboard will be uniformlyand evenly distributed.

In using this machine in the manufacture of These dwell positions permitblackboards it is contemplated that several coatings of material will beapplied to the surface of the slab of blackboard material, asforexample, a number of coats of color composition and a final coat ofmaterial containing an abrasive element such as carborundum. It will beobvious that one machine may be used for the application of eachsuccessive coat or separate machines may, if desired, be used forapplying each coat.

While we have illustrated in the drawings and 8 described, in thisinstance, an embodiment of our invention which is particularlyadvantageous for use in forming blackboard surfaces, it is to beunderstood that in so doing, we do not contemplate limiting its use forthis purpose only as it 9 will be readily appreciated by those skilledin the art that our invention is with equal facility adapted for use indepositing materials on the surfaces of various and sundry articles.

Now, it is of course "to be understood that 9 although we have describedin detail the preferred embodiment of our invention, the invention isnot to be thus limited but only insofar as defined by the scope andspirit of the appended claims.

We claim as our invention:

1. In a spraying machine, a pivotally mounted -arm, a rack and pinionconnection for oscillating said arm, a spray nozzle carried by said arm,conveyor means for continuously feeding stock mate- 1i rial under saidnozzle, and means for driving said conveyor and said arm through saidrack and pinion connection.

2. In a spraying machine, a pivotally mounted arm, a pinion connected tosaid arm, a rack meshing with said pinion, a cam mechanism forreciprocating said rack, a spray nozzle carried by said arm, conveyormeans for continuously feeding stock material past the nozzle, and meansfor actuating said conveyor and cam.

3; A machine for spraying the surface of blackboards comprising aconveyor system for continuously moving a blackboard in one direction ata predetermined speed, a spray nozzle disposed above said conveyor,means for moving said nozzle 15 back and forth at a uniform speed in adirection transversely to the path of movement of said blackboard, saidmeans having parts positioned and cooperative in such a manner as tomove said nozzle outwardly past the lateral edges of said 15 blackboardsand provide positions of dwell at the limits of travel of said nozzle,and means for collecting the material discharged from said nozzle atsaid dwell positions.

4. A machine for spraying the surface of black- 1 boards comprising aconveyor system for moving a blackboard continuously in one direction, avertically'disposed and oscillatable shaft, a spray nozzle mounted onsaid shaft for horizontal swinging movement, a pinion on said shaft, 9.]reciprocable rack engaging said pinion a vcam operable to move said rackin one direction, spring means to resist said movement, the pinion, rackand cam being so proportioned as to cause the nozzle to move outwardlypast the lateral edges 1 of the blackboard, means to collect thematerial discharged from the nozzle at the outer margins of its swing,and means to drive said conveyor and cam.

- JOHN F. JOHNSON.

ROBERT B. LAWTON.

